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Database Engine & Capacity Lab

Connect durability, MVCC, plan evidence, and connection budgets.

Concept
database engine capacity
Difficulty
Advanced
Play time
10-12 minutes
Path
Database Reliability

Interactive scenario

Playable game area: Make the next backend decision

Use the controls below. Feedback appears immediately and final scores stay in this browser.

Concept notes

Why this decision matters

Database Engine & Capacity Lab is focused practice for database engine capacity. It explains why each answer is safe, risky, or production-ready.

Connect durability, MVCC, plan evidence, and connection budgets.

Learning objectives

  • Locate the configured transaction durability boundary.
  • Recognize MVCC retention and bloat pressure.
  • Budget query and connection concurrency from evidence.

How to play

  1. Inspect the evidence for each scenario.
  2. Choose or order the defensible actions.
  3. Review the explanation before continuing.

Scoring

  • Each correct boundary adds 250 points.
  • Missed decisions enter local review.
  • A perfect session scores 1,000.

Backend concept notes

Connect durability, MVCC, plan evidence, and connection budgets.

The game rewards explicit boundaries, observable evidence, and recoverable operations.

Common mistakes

  • Treating timing as a correctness guarantee.
  • Changing capacity without identifying the constrained dependency.
  • Declaring recovery from one infrastructure signal.

Review misses from this game

Related Backend Study Lab tools

Use tools from the main site when you want to inspect real inputs.

Keep practicing nearby backend concepts while the mental model is fresh.

Databases Advanced

Query Plan Investigator

Investigate PostgreSQL query plans, cardinality gaps, scan choices, join amplification, and rollout evidence.

Time
9-12 minutes
Concept
SQL query planning and cardinality
  • Data & Performance
  • SQL Indexes
  • Performance
  • Databases
Play Query Plan Investigator

FAQ

Short answers for how this game fits backend interview and study practice.

Does this game contact a real production system?

No. Every scenario is deterministic and runs locally in the browser.

How should I use the related readings?

Start with the primary article, then use the deeper readings to review the boundaries exercised here.

Leaderboard

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